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Study on damage mechanism and damage distribution of the rear plate under impact of debris cloud

Defence Technology（防务技术） 2024年第5期35卷 151-167页

作者： Chenyang wu Xiaowei Chen Qiguang He State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyHaidian DistrictBeijing 100081China School of Mechatronical Engineering Beijing Institute of TechnologyHaidian DistrictBeijing 100081China Institute of Fluid Physics China Academy of Engineering PhysicsMianyang 621900SichuanChina

The debris cloud generated by the hypervelocity impact(HVI)of orbiting space debris directly threatens the spacecraft.A full understanding of the damage mechanism of rear plate is useful for the optimal design of protective *** this study,the hypervelocity yaw impact of a cylindrical aluminum projectile on a double-layer aluminum plate is simulated by the FE-SPH adaptive method,and the damage process of the rear plate under the impact of the debris cloud is analyzed based on the debris cloud *** damage process can be divided into the main impact stage of the debris cloud and the structural response of the rear *** main impact stage lasts a short time and is the basis of the rear plate *** the stage of structure response,the continuous deformation and inertial motion of the rear plate dominate the perforation of the rear *** further analyze the damage mechanism and damage distribution characteristics of the rear plate in ***,the connection between velocity space and position space of the debris cloud is established,which promotes the general analysis of the damage law of debris *** on the relationship,the features of typical damage areas are identified by the localized fine *** the cumulative effect and structural response cause the perforation of rear plate;in the non-perforated area,cratering by the impact of hazardous fragments is the main damage mode of the rear plate.

关键词： Damage of rear plate Debris cloud Secondary impact Hypervelocity yaw impact FE-SPH adaptive method

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Study on the effective elastic performance of composites containing decagonal symmetric two-dimensional quasicrystal coatings

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Applied Mathematics and Mechanics(English Edition) 2024年第9期45卷 1655-1664页

作者： Yurun wu Lu LI Lianhe LI School of Mathematics and Science Inner Mongolia Normal UniversityHohhot 010022China Inner Mongolia Applied mathematics Center Hohhot 010022China Key Laboratory of Infinite Dimensional Hamiltonian System and Its Algorithm Application Ministry of EducationHohhot 010022China

On account of the Mori-Tanaka approach,the effective elastic performance of composites containing decagonal symmetric two-dimensional(2D)quasicrystal(QC)coatings is *** expressions for the effective elastic constants of rare-earth QC reinforced magnesium-based composites are *** discussion is presented on the effects of the volume fraction of the inclusions,the aspect ratio of the inclusions,the coating thickness,and the coating material parameters on the effective elastic constants of the *** results indicate that considering the coating increases the effective elastic constants of the composites to some extent.

关键词： Mori-Tanaka approach coated inclusion decagonal symmetric twodimensional(2D)quasicrystal(QC)

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Improve Chinese Aspect Sentiment Quadruplet Prediction via Instruction Learning Based on Large Generate Models

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Computers, Materials & Continua 2024年第3期78卷 3391-3412页

作者： Zhaoliang wu Yuewei wu Xiaoli Feng Jiajun Zou Fulian Yin College of Information and Communication Engineering Communication University of ChinaBeijing100024China The State Key Laboratory of Media Convergence and Communication Communication University of ChinaBeijing100024China Department of Electronic Engineering Tsinghua UniversityBeijing100084China

Aspect-Based Sentiment Analysis(ABSA)is a fundamental area of research in Natural Language Processing(NLP).Within ABSA,Aspect Sentiment Quad Prediction(ASQP)aims to accurately identify sentiment quadruplets in target sentences,including aspect terms,aspect categories,corresponding opinion terms,and sentiment ***,most existing research has focused on English ***,while ASQP has seen significant progress in English,the Chinese ASQP task has remained relatively *** inspiration from methods applied to English ASQP,we propose Chinese generation templates and employ prompt-based instruction learning to enhance the model’s understanding of the task,ultimately improving ASQP performance in the Chinese ***,under the same pre-training model configuration,our approach achieved a 5.79%improvement in the F1 score compared to the previously leading ***,when utilizing a larger model with reduced training parameters,the F1 score demonstrated an 8.14%***,we suggest a novel evaluation metric based on the characteristics of generative models,better-reflecting model *** results validate the effectiveness of our approach.

关键词： ABSA ASQP LLMs sentiment analysis Chinese comments

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A buffer overflow detection and defense method based on RiSC-V instruction set extension

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Cybersecurity 2024年第2期7卷 28-43页

作者： Chang Liu Yan-Jun wu Jing-Zheng wu Chen Zhao Intelligent Software Research Center Institute of SoftwareChinese Academy of SciencesBejingChina University of Chinese Academy of Sciences BeijingChina State Key Laboratory of Computer Science Institute of SoftwareChinese Academy of SciencesBeijingChina

Buffer overflow poses a serious threat to the memory security of modern operating *** overwrites the con-tents of other memory areas by breaking through the buffer capacity limit,destroys the system execution environ-ment,and provides implementation space for various system attacks such as program control flow *** makes it a wide range of harms.A variety of security technologies have been proposed to deal with system security problems including buffer *** example,No eXecute(NX for short)is a memory management technology commonly used in Harvard *** can refuse the execution of code which residing in a specific memory,and can effectively suppress the abnormal impact of buffer overflow on control ***,in recent years,it has also been used in the field of system security,deriving a series of solutions based on NX technology,such as ExecShield,DEP,StackGuard,***,these security solutions often rely too much on the processor archi-tecture so that the protection coverage is insufficient and the accuracy is *** in the emerging system architecture field represented by RiSC-V,there is still a lack of effective solutions for buffer overflow *** the continuous rapid development of the system architecture,it is urgent to develop defense methods that are applicable to different system application environments and oriented to all executable memory spaces to meet the needs of system security ***,we propose BOP,A new system memory security design method based on RISC-V extended instructions,to build a RISC-V buffer overflow detection and defense system and deal with the buffer overflow threat in *** to this method,NX technology can be combined with program control flow analysis,and Nx bit mechanism can be used to manage the executability of memory space,so as to achieve a more granular detection and defense of buffer overflow attacks that may occur in RISC-V system

关键词： RISc-V Operating system security Buffer overflow Control flow hijacking Nx bit Xibop

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Research progresses on cathode materials of aqueous zinc-ion batteries

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Journal of Energy Chemistry 2024年第10期97卷 237-264页

作者： Zengyuan Fan Jiawei Wang Yunpeng wu Xuedong Yan Dongmei Dai Xing-Long wu Jilin Provincial Science and Technology Innovation Centre of Optical Materials and Chemistry Jilin Provincial International Joint Research Center of Photo-functional Materials and Chemistry School of Chemistry and Environmental Engineering Changchun University of Science and Technology Chongqing Research Institute Changchun University of Science and Technology Institute of Energy Storage and Conversion Technology College of Chemical EngineeringNingbo Polytechnic School of Chemistry and Chemical Engineering Henan Normal University MOE Key Laboratory for UV Light-Emitting Materials and Technology School of Physics Northeast Normal University

Electrochemical energy storage and conversion techniques that exhibit the merits such as high energy density,rapid response kinetics,economical maintenance requirements and expedient installation procedures will hold a pivotal role in the forthcoming energy storage technologies *** recent years,aqueous zinc-ion batteries（AZIBs） have garnered substantial attention as a compelling candidate for large-scale energy storage systems,primarily attributable to their advantageous featu res encompassing cost-effectiveness,environmental sustainability,and robust safety ***,one of the primary factors hindering the further development of AZIBs originates from the challenge of cathode ***,the three mainstream types of mainstream cathode materials,in terms of manganese-based compounds,vanadium-based compounds and Prussian blue analogues,surfer from the dissolution of Mn2+,in the low discharge voltage,and the low specific capacity,*** strategies have been developed to compensation the above intrinsic defects for these cathode materials,including the ionic doping,defect engineering,and materials ***,this review first provides a systematic summarization of the zinc storage mechanism in AZIBs,following by the inherent merit and demerit of three kind of cathode materials during zinc storage analyzed from their structure characteristic,and then the recent development of critical strategies towards the intrinsic insufficiency of these cathode *** this review,the methodologies aimed at enhancing the efficacy of manganese-based and vanadium-based compounds are emphasis ***,the article outlines the future prospective directions as well as strategic proposal for cathode materials in AZIBs.

关键词： Aqueous zinc−ion batteries Cathode materials Optimization strategies

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A novel Ag/ZnO core-shell structure for efficient sterilization synergizing antibiotics and subsequently removing residuals

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Green Energy & Environment 2024年第2期9卷 366-377页

作者： Wenmei Han Wenli Wang Jie Fan Runping Jia Xuchun Yang Tong wu Qingsheng wu School of Chemical Science and Engineering Shanghai Key Laboratory of Chemical Assessment and SustainabilityInstitute of Advanced StudyTongji UniversityShanghai200092China College of Textile and Clothing Engineering China National Textile and Apparel Council Key Laboratory of Natural DyesSoochow UniversitySuzhou215123China Department of Urology Shanghai First People’s HospitalSchool of MedicineShanghai Jiaotong UniversityShanghai200080China School of Materials Science and Engineering Shanghai Institute of TechnologyShanghai201418China

The massive use of antibiotics has led to the aggravation of bacterial resistance and also brought environmental pollution *** poses a great threat to human *** the dosage of antibiotics is reduced by increasing its bactericidal performance,the emergence of drug resistance is certainly delayed,so that there's not enough time for developing drug resistance during ***,we selected typical representative materials of metal Ag and semiconductor ZnO nano-bactericides to design and synthesize Ag/ZnO hollow core-shell structures(AZ for short).Antibiotics are grafted on the surface of AZ through rational modification to form a composite sterilization *** research results show that the antibacterial efficiency of the composite system is significantly increased,from the sum(34.7%+22.8%-57.5%)of the antibacterial efficiency of AZ and gentamicin to 80.2%,net synergizes 22.7%,which fully reflects the effect of 1+1>***,the dosage of antibiotics can be drastically reduced in this way,which makes both the possibility of bacterial resistance and medical expenses remarkably ***,residual antibiotics can be degraded under simple illumination using AZ-self as a photocatalyst,which cuts off the path of environmental *** short,such an innovative route has guiding significance for drug resistance.

关键词： Ag/ZnO hollow Core-shell structures Antibiotics Gentamycin Synergistic sterilization Photodegradation

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Semantic segmentation-based semantic communication system for image transmission

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Digital Communications and Networks 2024年第3期10卷 519-527页

作者： Jiale wu Celimuge wu Yangfei Lin Tsutomu Yoshinaga Lei Zhong Xianfu Chen Yusheng Ji The University of Electro-Communication Tokyo182-8585Japan Toyota Motor Corporation Tokyo112-8701Japan VTT Technical Research Centre of Finland OuluFinland National Institute of Informatics(NII) Tokyo101-8430Japan

With the rapid development of artificial intelligence and the widespread use of the Internet of Things, semantic communication, as an emerging communication paradigm, has been attracting great interest. Taking image transmission as an example, from the semantic communication's view, not all pixels in the images are equally important for certain receivers. The existing semantic communication systems directly perform semantic encoding and decoding on the whole image, in which the region of interest cannot be identified. In this paper, we propose a novel semantic communication system for image transmission that can distinguish between Regions Of Interest (ROI) and Regions Of Non-Interest (RONI) based on semantic segmentation, where a semantic segmentation algorithm is used to classify each pixel of the image and distinguish ROI and RONI. The system also enables high-quality transmission of ROI with lower communication overheads by transmissions through different semantic communication networks with different bandwidth requirements. An improved metric θPSNR is proposed to evaluate the transmission accuracy of the novel semantic transmission network. Experimental results show that our proposed system achieves a significant performance improvement compared with existing approaches, namely, existing semantic communication approaches and the conventional approach without semantics.

关键词： Semantic Communication Semantic segmentation Image transmission Image compression Deep learning

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L vector spaces and L fields

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Science China Mathematics 2024年第10期67卷 2195-2216页

作者： Yinhe Peng Liuzhen wu Academy of Mathematics and Systems Science Chinese Academy of SciencesBeijing 100190China

We construct in ZFC(the Zermelo-Fraenkel system with choice) an L topological vector space—a topological vector space that is an L space—and an L field—a topological field that is an L space. This generalizes earli... 详细信息

关键词： minimal walk topological vector space topological eld L space L vector space L eld

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Topological Dirac-vortex microcavity laser for robust on-chip optoelectronics

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Light(Science & Applications) 2024年第4期13卷 591-592页

作者： Yuanpeng wu Zetian Mi Department of Electrical Engineering and Computer Science University of Michigan1301 Beal AvenueAnn ArborMI 48109USA

Dirac-vortex microcavity laser based on InAs/InGaAs quantum dots have been experimentally realized on silicon *** topological laser features a large spectral range and high robustness against variations such as cavity... 详细信息

关键词： laser optoelectronics cavity

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In Situ Reconfiguration of Assembling Pattern for Modular Continuum Robots

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Journal of Bionic Engineering 2024年第4期21卷 1695-1706页

作者： Jie Zhang Jiannan Cai Ke Ma Jinzhao Yang Zhigang wu Haijun Peng Jianing wu School of Mechanical Engineering Dalian University of TechnologyDalian116024People’s Republic of China School of Advanced Manufacturing Sun Yat-Sen UniversityShenzhen518107People’s Republic of China School of Aeronautics and Astronautics Sun Yat-Sen UniversityShenzhen518107People’s Republic of China

Modular continuum robots possess significant versatility across various scenarios;however,conventional assembling methods typically rely on linear connection between *** limitation can impede the robotic interaction capabilities,especially in specific engineering ***,inspired by the assembling pattern between the femur and tibia in a human knee,we proposed a multidirectional assembling *** strategy encompasses linear,oblique,and orthogonal connections,allowing a two-module continuum robot to undergo in-situ reconfiguration into three distinct initial *** anticipate the final configuration resulting from diverse assembling patterns,we employed the positional formulation finite element framework to establish a mechanical model,and the theoretical results reveal that our customizable strategy can offer an effective route for robotic *** showcased diverse assembling patterns for coping with interaction *** experimental results indicate that our modular continuum robot not only reconfigures its initial profile in situ but also enables on-demand regulation of the final *** capabilities provide a foundation for the future development of modular continuum robots,enabling them to be adaptable to diverse environments,particularly in unstructured surroundings.

关键词： Assembling patterns Continuum robot In-situ reconfiguration Tensegrity structure Varying stiffness

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